java四则运算

import javax.swing.JOptionPane;

public class Yunsuan {

     public static void main( String args[] )

       {

          String firstNumber,   

                 secondNumber;  

          int number1,         

              number2,          

              sum,

              cha,

              ji,

              shang;

          firstNumber =          JOptionPane.showInputDialog( "Enter first integer" );

          secondNumber =     JOptionPane.showInputDialog( "Enter second integer" );

          number1 = Integer.parseInt( firstNumber ); 

          number2 = Integer.parseInt( secondNumber );

          sum = number1 + number2;

          cha = number1 - number2;

          ji = number1 * number2;

          shang = number1 / number2;          

                  JOptionPane.showMessageDialog(

                             null, "和为 " + sum +" "+

                             "差为：" +cha +" "+

                             "积为：" + ji + " "+ 

                             "商为" +shang +" ",

                             "Results",

                             JOptionPane.PLAIN_MESSAGE 

                             )；

          System.exit( 0 );   // terminate the program

       }

}